Lyapunov Functions in Piecewise Linear Systems: From Fixed Point to Limit Cycle

This paper provides a first example of constructing Lyapunov functions in a class of piecewise linear systems with limit cycles. The method of construction helps analyze and control complex oscillating systems through novel geometric means. Special attention is stressed upon a problem not formerly solved: to impose consistent boundary conditions on the Lyapunov function in each linear region. By successfully solving the problem, the authors construct continuous Lyapunov functions in the whole state space. It is further demonstrated that the Lyapunov functions constructed explain for the different bifurcations leading to the emergence of limit cycle oscillation

Are the Water Trips in the Dryland Kenya for Sustainable Development, Journeys in Vain or Trips to Oblivion?

Kenya’s households’ (HH) water access status is appalling. As a gender based task, women and children make billions of trips to satisfy HH water needs, taking a heavy toll on societal growth and development. Kenya’s 4872 randomly sampled HHs from six Arid and semi-Arid land (ASALs) counties were studied using interviews and focused group discussions. The aim was to determine the burden of water fetching in Kenya-ASALs. On a daily basis, HHs make 3.06 water trips of 49.42+0.36 minutes, largely shouldered by females (2.69 trips); males (0.22); women (2.51); men (0.12) and children (0.43 trips). The 2.5 million Kenyan-ASAL households make 7,658,500 trips daily (2,795,352,500 annually). Of these, children make 395,477,500; women (2,287,637,500); and men (112,237,500 trips). With this kind of burden, the children and women are denied opportunity for self-development. Water supply mainstreaming is an urgent priority in Kenya-ASALs.Key words: Water Supply, Sustainability, Gender, Development, Kenya ASALS

Deterministic spin-wave interferometer based on Rydberg blockade

The spin-wave (SW) NOON state is an $N$-particle Fock state with two atomic spin-wave modes maximally entangled. Attributed to the property that the phase is sensitive to collective atomic motion, the SW NOON state can be utilized as a novel atomic interferometer and has promising application in quantum enhanced measurement. In this paper we propose an efficient protocol to deterministically produce the atomic SW NOON state by employing Rydberg blockade. Possible errors in practical manipulations are analyzed. A feasible experimental scheme is suggested. Our scheme is far more efficient than the recent experimentally demonstrated one, which only creates a heralded second-order SW NOON state.Comment: 5 pages, 2 figure

Particle-resolved thermal lattice Boltzmann simulation using OpenACC on multi-GPUs

We utilize the Open Accelerator (OpenACC) approach for graphics processing unit (GPU) accelerated particle-resolved thermal lattice Boltzmann (LB) simulation. We adopt the momentum-exchange method to calculate fluid-particle interactions to preserve the simplicity of the LB method. To address load imbalance issues, we extend the indirect addressing method to collect fluid-particle link information at each timestep and store indices of fluid-particle link in a fixed index array. We simulate the sedimentation of 4,800 hot particles in cold fluids with a domain size of $4000^{2}$, and the simulation achieves 1750 million lattice updates per second (MLUPS) on a single GPU. Furthermore, we implement a hybrid OpenACC and message passing interface (MPI) approach for multi-GPU accelerated simulation. This approach incorporates four optimization strategies, including building domain lists, utilizing request-answer communication, overlapping communications with computations, and executing computation tasks concurrently. By reducing data communication between GPUs, hiding communication latency through overlapping computation, and increasing the utilization of GPU resources, we achieve improved performance, reaching 10846 MLUPS using 8 GPUs. Our results demonstrate that the OpenACC-based GPU acceleration is promising for particle-resolved thermal lattice Boltzmann simulation.Comment: 45 pages, 18 figure

Microbial content of abattoir wastewater and its contaminated soil in Lagos, Nigeria

Microbial content of wastewater in two abattoirs and the impact on microbial population of receiving soil was studied in Agege and Ojo Local Government Areas in Lagos State, Nigeria. Wastewatersamples were collected from each of the abattoirs over three months period and examined for microbial content. Soil samples contaminated with the wastewaters were also collected and analysed formicrobial content as compared to soil without wastewater contamination in the neighbourhood (control). Some physico-chemical parameters of the samples such as total dissolved solid, chemical oxygen demand etc were examined. The wastewater samples from both abattoirs were highlycontaminated; Agege abattoir showed mean bacterial count of 3.32x107 cfu/ml and Odo abattoir showed mean count of 2.7x107 cfu/ml. The mean fungal populations were 1.6x 105 and 1.2x05 cfu/ml for Agege and Odo abattoirs respectively. In the contaminated soil sample, mean bacterial count was 3.36x107 cfu/ml compared to the 1.74x106 cfu/ml of the control sample. High microbial load in abattoir wastewater with negative effects on microbial population in soil, in this study, further confirmed the need to treat wastewater rather than discharging it to the environment

Robust creation of entanglement between remote memory qubits

In this Letter we propose a robust quantum repeater architecture building on the original DLCZ protocol [L.M. Duan \textit{et al.}, Nature \textbf{414}, 413 (2001)]. The architecture is based on two-photon Hong-Ou-Mandel-type interference which relaxes the long distance stability requirements by about 7 orders of magnitude, from sub wavelength for the single photon interference required by DLCZ to the coherence length of the photons. Our proposal provides an exciting possibility for robust and realistic long distance quantum communication.Comment: Comments are welcome, to appear in Phys. Rev. Lett., accepted versio

Hand Tumours in Lagos, Nigeria: A Clinicopathologic Study

Background: Hand tumours occur infrequently and are commonly benign, however when malignant they could be life threatening. This study was aimed at determining the prevalence, demographics, the clinical presentations and treatment outcome of hand tumours among patients attending the hand service of the Lagos University Teaching Hospital.Methods: We studied the clinical and pathological records of a 124  consecutive hand tumours that presented at hand clinic of the Lagos University Teaching Hospital(LUTH) between June 2003 and June 2013 .Results: A total of 124 patients were seen of which 98 had excision biopsies . The male to female sex ratio was 1: 1.3. The mean age at presentation was 32.7 years sd ± 8.44 years. An overwhelming majority (94.9%) had their procedures done under local/regional anaesthesia. Two patients died and three of the tumours recurred during the follow up period. The commonest histopathological diagnoses included ganglion cyst, giant cell tumor of the tendon sheath and pyogenic granuloma constituting 23.8%. 15.7% and 6.7% of the cases seen respectively.Conclusion: Hand tumours in Lagos tend to affect young adults with a slight female preponderance. Majority of the tumours were benign. Primary hand malignancy was uncommon and mortality was low. Nearly all (97%) of the surgically treated patients returned to their premorbid occupation.Key words: Hand tumours, biopsy, soft tissue

Inhibitory effects of Phyllanthus amarus extracts on the growth of some pathogenic microorganisms

This study evaluated the inhibitory effects of Phyllanthus amarus extracts on Staphylococcus aureus,  Streptococcus pneumoniae, Streptococcus pyogenes, Pseudomonas aeruginosa and Candida albicans. These effects were compared with those of ampicillin, gentamicin and pefloxacin. Phytochemical  analysis showed that the plant contained flavonoids, steroids, terpenes, alkaloids, benzenoids, saponins and lipids. This plant was found to have remarkable inhibitory effects on the growth of all the  organisms tested; S. aureus was the most susceptible (MIC 20ug/ml) while Pseudomonas aeruginosa and C. albicans were the least susceptible (MIC 30ug/ml). The organisms were inhibited in a dose-dependent manner, the inhibition was almost directly proportional to the extract concentration. The aqueous extract had no significant increase inhibitory effects compared to the ethanol extract (p > 0.05). The standard antibiotics had no greater inhibitory effects on the test organisms in relation to the plant extracts (p>0.05). The in vitro analysis revealed that Phyllanthus amarus possesses an antimicrobial activity comparable with those of standard antibiotic discs. Further works is recommended to determine its suitability in chemotherapy. Keywords: Inhibitory effects, Phyllanthus amarus extract, Pathogenic microorganisms